Voltage-dependent non-linear resistance ceramic composition

ABSTRACT

This is a voltage-dependent non-linear resistance ceramic composition wherein resistance of crystal is decreased by containing SrTiO 3  as host material, and Nb 2  O 5  and Ta 2  O 5  as semiconductorization accelerating agent, and further by adding as additive one kind or more oxide of element selected from the group consisting of MnO 2 , Ga, Pt, Tl, Si, Ti, Li, La, Cu, Y, Cs, Au, Mo, S, Be, Al, Na, K, Ca, Cd, In, Ba, Pb, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf, Ru, Mg, Zr, Sn, Sb and W, these additive is segregated at crystal granule boundaries, thereby making the crystal granule boundaries to high resistance. 
     Accordingly, by the high resistance layer at the crystal boundaries the varistor characteristic is obtainable, and a capacitance characteristic is obtainable between the crystal granule-crystal granule boundary-crystal granule. 
     From this, an element having both functions of the varistor characteristics and the capacitor characteristics are obtainable, and performs effect in surge absorption and noise elemination.

This is a continuation of application Ser. No. 708,079, filed Feb. 26, 1985 which was abandoned upon the filing hereof.

TECHNICAL FIELD

The present invention relates to a voltage dependent non-linear resistance ceramic composition for use in surge absorbing and noise elimination in various electric apparatuses and electronic apparatuses.

BACKGROUND ART

Heretofore, in various electric apparatuses and electronic apparatuses, in order to absorb extraordinary high voltage, elimination of noise, elimination of arc, and the like, SiC varistors or varistors of ZnO system having a voltage-dependent non-linear resistance characteristics are used. Voltage-current characteristic of such varistors can be approximately represented by the following equation:

    I=(V/C).sup.α,

wherein I is current, V is voltage, C is a constant proper for the varistor, and α is a voltage non-linearity exponent.

The α of the SiC varistor is about 2-7, and for the ZnO system varistor there is ones that reaching 50. Though such varistors has superior characteristic for absorbing relatively high voltage called surge, for voltages lower than varistor voltage (for instance, absorption of noise) almost no effect is represented since its dielectric constant is low and its inherent capacitance is small, and their dielectric loss tan δ are so large as 5-10%.

On the other hand, for elimination of low voltage noise, static electricity, or the like, by appropriately selecting composition and firing condition, semiconductor ceramic capacitors having apparent dielectric constant of about 5×10⁴ -6×10⁴ and tan δ of about 1% are utilized.

However, these semiconductor ceramic capacitor is liable to be destroyed or become to be non-functional as capacitors when extraordinary high voltage such as surge is impressed thereon or a current above a certain limit is impressed on the element. For such reason, in the electric apparatuses or electronic apparatuses, for the purpose of both the absorbing of high voltage surge and the elimination of low volage noise, the varistors are used being combined with capacitors and other component (for instance, coil), and for instance, a noise filter has such configuration.

FIG. 1 shows general noise filter circuit, FIG. 2 shows a conventional noise filter circuit constituted by combining a varistor, capacitors and a coil, and 1 is the coil, 2 and the capacitors and 3 is the varistor.

When a noise input A shown in FIG. 5 is impressed on these circuits, output characteristics from general noise filter circuit of FIG. 1 is such as C of FIG. 5, and noise is not eliminated sufficiently. Output characteristic from the conventional noise filter circuit including a varistor shown in FIG. 2 is such as B of FIG. 5, and though noise is eliminated, such configuration has a shortcoming that it has large number of components in the inside of the apparatus and besides is contrary to tendency of miniaturization of the apparatus.

Accordingly, an electronic component, which absorbs extraordinary high voltage, can eliminate low voltage, such as noise and has small number of components, and capable of miniaturization, is demanded.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention intends to provide a voltage-dependent non-linear resistance ceramic composition comprising 90.800-99.996 mol % of SrTiO₃ and as metal oxides for semiconductorization acceleration 0.001-0.200 mol % of Nb₂ O₅ and 0.001-5.000 mol % of Ta₂ O₅, and is characterized by containing 0.001-2.000 mol % in the form of oxide of at least one kind of element selected from the group consisting of Ga, Pt, Tl, Si, Ti, Cs, Au, S, Be, Al, Ca, Cd, In, Ba, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf, Ru, Mg, Zr, Sn, Sb and.

BRIEF EXPLANATION OF THE DRAWING

FIG. 1 is a circuit diagram of a general noise filter, FIG. 2 is a circuit diagram of a noise filter using the conventional varistors and the capacitors, FIG. 3 is a sectional view of an element using voltage dependent non-linear resistance ceramic composition in accordance with the present invention, FIG. 4 is a circuit diagram of a noise filter using the voltage dependent non-linear resistance ceramic composition in accordance with the present invention, FIG. 5 is a characteristic chart showing situation of input noise and output in accordance with circuit of noise filters of the present invention and the prior art.

THE BEST MODE FOR EMBODYING THE INVENTION

As a result of accumulating various experiments the inventors propose a voltage dependent non-linear resistance ceramic composition in a different system from the conventional composition by making strontium-titanate (SrTiO₃) as host material, and adding either one of Nb₂ O₅ and Ta₂ O₅ as semi-conductorization accelerating agent, and by further adding MnO₂ and appropriate amount of other additives; hereafter the present invention is described with respect to embodiments.

EXAMPLE 1

After measuring SrTiO₃, Nb₂ O₅, Ta₂ O₅, MnO₂ and Tl₂ O to become composition ratio as shown in the below-mentioned Table 1, they are blended for 6 hours in wet method in a ball-mill or the like, and after drying is calcinated for 1-5 hours at 1000°-1250° C. in the air. Thereafter, after grinding for 4 hours in wet method in ball mill or the like and subsequently drying, and after granulating by adding 8 wt % of organic binder (for instance, polyvinylalcohol), press-forming to the size of 8.0 (mm) φ×1.0 (mm) t with a pressing force of 1.0 t/cm². The granulated body is fired in a reducing atmosphere (for instance, N₂ :H₂ =10:1) at 1300°-1450° C. for 1-6 hours. The fired body thus obtained has a specific resistance of 0.1-0.8 Ω.cm, and average granular size is 20-50 μm. Then, the dired body is further fired in air at 1000°-1300° C. for 0.5-5 hours, to obtain fired body 4 of FIG. 3. Furthermore, the both faces of the fired body 4 are ground with abrasive such as SiC and electrodes 5, 6 are formed by using a conductive metal such as Ag. Diameter of the above-mentioned electrodes 5, 6 are selected to be 5.0 (mm) φ.

Characteristics of the element thus obtained are shown in Table 1.

                                      TABLE 1                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                          Characteristic value                                   No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Ta.sub.2 O.sub.5                                                                   MnO.sub.2                                                                          Tl.sub.2 O                                                                         V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                            tan δ (%)                       __________________________________________________________________________      1* 99.795                                                                             0.100                                                                              0   0.100                                                                              0.005                                                                              1240    3.5                                                                               1 × 10.sup.3                                                                   5.4                                    2* 99.300                                                                             0.100                                                                              0   0.500                                                                              0.100                                                                              1460    5.7                                                                               1 × 10.sup.3                                                                   10.9                                   3* 99.899                                                                             0.100                                                                              0.001                                                                              0   0    90     3.0                                                                               1 × 10.sup.3                                                                   4.2                                    4* 99.898                                                                             0.100                                                                              0.001                                                                              0   0.001                                                                              110     4.2                                                                               1 × 10.sup.3                                                                   3.6                                    5* 99.799                                                                             0.100                                                                              0.001                                                                              0   0.100                                                                              117     4.9                                                                               2 × 10.sup.3                                                                   3.0                                    6* 97.899                                                                             0.100                                                                              0.001                                                                              0   2.000                                                                              135     5.6                                                                               2 × 10.sup.3                                                                   3.0                                    7* 96.899                                                                             0.100                                                                              0.001                                                                              0   3.000                                                                              175     5.5                                                                               2 × 10.sup.3                                                                   4.6                                    8* 99.898                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0   100     5.7                                                                               4 × 10.sup.3                                                                   4.1                                   9   99.897                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0.001                                                                              120     8.6                                                                               8 × 10.sup.3                                                                   3.5                                   10  99.798                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0.100                                                                              128     9.7                                                                               9 × 10.sup.3                                                                   3.0                                   11  97.799                                                                             0.100                                                                              0.001                                                                              0.001                                                                              2.000                                                                              142     9.7                                                                               9 × 10.sup.3                                                                   2.9                                   12* 96.799                                                                             0.100                                                                              0.001                                                                              0.001                                                                              3.000                                                                              164     9.5                                                                               5 × 10.sup.3                                                                   3.9                                   13* 98.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0   150     8.2                                                                               4 × 10.sup.3                                                                   4.5                                   14  98.898                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0.001                                                                              157     8.7                                                                               8 × 10.sup.3                                                                   4.0                                   15  98.799                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0.100                                                                              167     9.6                                                                               9 × 10.sup.3                                                                   3.4                                   16  96.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              2.000                                                                              173     9.8                                                                               1.0 × 10.sup.4                                                                 3.0                                   17* 95.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              3.000                                                                              182     9.2                                                                               6 × 10.sup.3                                                                   7.1                                   18* 97.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0   190     8.8                                                                               5 × 10.sup.3                                                                   10.1                                  19  97.898                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0.001                                                                              198     8.0                                                                               9 × 10.sup.3                                                                   10.1                                  20  97.799                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0.100                                                                              202     8.7                                                                               9 × 10.sup.3                                                                   9.3                                   21  95.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              2.000                                                                              204     8.7                                                                               1.0 × 10.sup.4                                                                 8.9                                   22* 94.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              3.000                                                                              255     7.9                                                                               5 × 10.sup.3                                                                   7.8                                   23* 98.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0    90     8.0                                                                               4 × 10.sup.3                                                                   4.0                                   24  98.898                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0.001                                                                              100     9.2                                                                               8 × 10.sup.3                                                                   2.7                                   25  98.799                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0.100                                                                              111     11.3                                                                              9 × 10.sup.3                                                                   2.3                                   26  96.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              2.000                                                                              127     11.6                                                                              1.1 × 10.sup.4                                                                 2.3                                   27* 95.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              3.000                                                                              156     9.1                                                                               6 × 10.sup.3                                                                   6.3                                   28* 97.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0   130     8.2                                                                               5 × 10.sup.3                                                                   4.2                                   29  97.899                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0.001                                                                              147     9.2                                                                               8 × 10.sup.3                                                                   2.9                                   30  97.800                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0.100                                                                              156     12.0                                                                              9 × 10.sup.3                                                                   2.5                                   31  95.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              2.000                                                                              162     11.5                                                                              1.1 × 10.sup.4                                                                 2.3                                   32* 94.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              3.000                                                                              175     9.0                                                                               7 × 10.sup.3                                                                   5.4                                   33* 96.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0   180     8.0                                                                               6 × 10.sup.3                                                                   10.0                                  34  96.899                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0.001                                                                              198     8.0                                                                               7 × 10.sup.3                                                                   9.5                                   35  96.800                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0.100                                                                              213     8.1                                                                               7 × 10.sup.3                                                                   9.0                                   36  94.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              2.000                                                                              233     8.5                                                                               7 ×  10.sup.3                                                                  8.9                                   37* 93.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              3.000                                                                              260     7.9                                                                               8 × 10.sup.3                                                                   8.8                                   38* 94.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0    75     7.2                                                                               7 × 10.sup.3                                                                   3.8                                   39  94.898                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0.001                                                                               85     7.7                                                                               7 × 10.sup.3                                                                   3.0                                   40  94.799                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0.100                                                                               96     9.3                                                                               8 × 10.sup.3                                                                   2.5                                   41  92.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              2.000                                                                              112     9.8                                                                               9 × 10.sup.3                                                                   2.4                                   42* 91.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              3.000                                                                              127     9.0                                                                               5 × 10.sup.3                                                                   3.5                                   43* 93.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0    82     7.6                                                                               7 × 10.sup.3                                                                   3.9                                   44  93.899                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0.001                                                                               94     8.4                                                                               9 × 10.sup.3                                                                   2.6                                   45  93.800                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0.100                                                                              112     10.2                                                                              1 × 10.sup.4                                                                   2.5                                   46  91.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              2.000                                                                              115     10.1                                                                              1.1 × 10.sup.4                                                                 2.5                                   47* 90.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              3.000                                                                              139     9.5                                                                               6 × 10.sup.3                                                                   4.3                                   48* 92.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0    95     8.4                                                                               7 × 10.sup.3                                                                   9.4                                   49* 92.899                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0.001                                                                              121     9.1                                                                               7 × 10.sup.3                                                                   9.3                                   50* 92.800                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0.100                                                                              131     10.2                                                                              8 × 10.sup.3                                                                   9.0                                   51* 90.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              2.000                                                                              138     10.2                                                                              8 × 10.sup.3                                                                   8.6                                   52* 89.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              3.000                                                                              195     8.5                                                                               4 × 10.sup.3                                                                   9.2                                   53* 92.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0    40     4.0                                                                               6 × 10.sup.3                                                                   6.2                                   54* 92.898                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0.001                                                                               60     4.3                                                                               6 × 10.sup.3                                                                   6.1                                   55* 92.799                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0.100                                                                               63     4.3                                                                               6 × 10.sup.3                                                                   5.9                                   56* 90.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              2.000                                                                               69     4.5                                                                               6 × 10.sup.3                                                                   5.9                                   57* 89.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              3.000                                                                              102     4.7                                                                               5 × 10.sup.3                                                                   7.8                                   58* 91.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0    49     4.4                                                                               6 × 10.sup.3                                                                   10.2                                  59* 91.899                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0.001                                                                               75     4.8                                                                               6 × 10.sup.3                                                                   10.1                                  60* 91.800                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0.100                                                                               81     5.2                                                                               6 × 10.sup.3                                                                   10.0                                  61* 89.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              2.000                                                                               93     5.8                                                                               5 × 10.sup.3                                                                   9.8                                   62* 88.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              3.000                                                                              124     5.0                                                                               4 × 10.sup.3                                                                   9.9                                   63* 95.800                                                                             0.100                                                                              1.000                                                                              3.000                                                                              0.100                                                                              211     4.2                                                                               5 × 10.sup.3                                                                   23.1                                  64* 92.900                                                                             0.100                                                                              1.000                                                                              3.000                                                                              3.000                                                                              244     5.3                                                                               4 × 10.sup.3                                                                   21.0                                  __________________________________________________________________________      *Comparison sample                                                       

Herein, evaluation of characteristics of the elements as varistor can be made by α and C in a voltage-current characteristic equation:

    I=(V/C).sup.α

(wherein I is current, V is voltage, C is a constant proper to the varistor and α is a non-linearity exponent). Since accurate measurement of C is difficult, in the present invention, characteristic assessment as varistor is made by the value of varistor voltage for unit thickness when 1 mA of varistor current is flowed (hereinafter is called as V₁ mA/mm.) and by a value of

    α=1/log (V.sub.10 mA/V.sub.1 mA)

(wherein V₁₀ mA is a varistor voltage when a varistor current of 10 mA is flowed and V₁ mA is a varistor voltage when varistor current of 1 mA is flowed).

And characteristic assessment as the capacitors are made by a dielectric constant ε and dielectric loss tan δ at a measurement frequency of 1 KHz. The above-mentioned data are those for firing temperature and time in the reducing atmosphere was 1400° C. and 2 hours, respectively and firing temperature and time in air was 1200° C. and 3 hours, respectively.

EXAMPLE 2

SrTiO₃, Nb₂ O₅, Ta₂ O₅, MnO₂ and Y₂ O₅ are made in a composition ratio shown in the below-mentioned Table 2, and mixing, forming and firings are carried out in a similar operation as the above-mentioned EXAMPLE 1, and measurements are made in the similar conditions and results are shown in Table 2.

                                      TABLE 2                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                          Characteristic value                                   No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Ta.sub.2 O.sub.5                                                                   MnO.sub.2                                                                          Y.sub.2 O.sub.3                                                                    V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                            tan δ (%)                       __________________________________________________________________________      1* 99.795                                                                             0.100                                                                              0   0.100                                                                              0.005                                                                              1350    3.5                                                                               1 × 10.sup.3                                                                   5.3                                    2* 99.300                                                                             0.100                                                                              0   0.500                                                                              0.100                                                                              1530    5.2                                                                               3 × 10.sup.3                                                                   9.2                                    3* 99.899                                                                             0.100                                                                              0.001                                                                              0   0    90     3.0                                                                               1 × 10.sup.3                                                                   4.2                                    4* 99.898                                                                             0.100                                                                              0.001                                                                              0   0.001                                                                              102     4.0                                                                               1 × 10.sup.3                                                                   2.7                                    5* 99.799                                                                             0.100                                                                              0.001                                                                              0   0.100                                                                              110     4.7                                                                               2 × 10.sup.3                                                                   2.0                                    6* 97.899                                                                             0.100                                                                              0.001                                                                              0   2.000                                                                              130     5.7                                                                               3 × 10.sup.3                                                                   2.1                                    7* 96.899                                                                             0.100                                                                              0.001                                                                              0   3.000                                                                              162     5.8                                                                               2 × 10.sup.3                                                                   2.2                                    8* 99.898                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0   100     5.7                                                                               4 × 10.sup.3                                                                   4.1                                   9   99.897                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0.001                                                                              105     8.4                                                                               8 × 10.sup. 3                                                                  2.6                                   10  99.798                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0.100                                                                              114     9.5                                                                               9 × 10.sup.3                                                                   2.0                                   11  97.799                                                                             0.100                                                                              0.001                                                                              0.001                                                                              2.000                                                                              138     9.7                                                                               1 × 10.sup.4                                                                   2.0                                   12* 96.799                                                                             0.100                                                                              0.001                                                                              0.001                                                                              3.000                                                                              152     10.1                                                                              6 × 10.sup.3                                                                   2.8                                   13* 98.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0   150     8.2                                                                               4 × 10.sup.3                                                                   4.5                                   14  98.898                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0.001                                                                              155     8.5                                                                               9 × 10.sup.3                                                                   3.1                                   15  98.799                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0.100                                                                              164     9.4                                                                               1 × 10.sup.4                                                                   2.6                                   16  96.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              2.000                                                                              173     10.0                                                                              1.1 × 10.sup.4                                                                 2.2                                   17* 95.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              3.000                                                                              178     10.4                                                                              6 × 10.sup.3                                                                   2.0                                   18* 97.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0   190     8.8                                                                               5 × 10.sup.3                                                                   10.1                                  19  97.898                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0.001                                                                              210     8.7                                                                               9 × 10.sup.3                                                                   9.0                                   20  97.799                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0.100                                                                              218     9.3                                                                               1.1 × 10.sup.4                                                                 8.9                                   21  95.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              2.000                                                                              232     10.2                                                                              1.1 × 10.sup.4                                                                 7.9                                   22* 94.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              3.000                                                                              260     10.0                                                                              8 × 10.sup.3                                                                   6.8                                   23* 98.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0    90     8.0                                                                               4 × 10.sup.3                                                                   4.0                                   24  98.898                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0.001                                                                               95     8.9                                                                               9 × 10.sup.3                                                                   2.9                                   25  98.799                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0.100                                                                              103     11.2                                                                              1.0 × 10.sup.4                                                                 2.0                                   26  96.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              2.000                                                                              125     11.8                                                                              1.1 × 10.sup.4                                                                 2.0                                   27* 95.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              3.000                                                                              149     10.1                                                                              7 × 10.sup.3                                                                   2.1                                   28* 97.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0   130     8.2                                                                               5 × 10.sup.3                                                                   4.2                                   29  97.899                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0.001                                                                              140     9.0                                                                               9 × 10.sup.3                                                                   3.0                                   30  97.800                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0.100                                                                              149     11.8                                                                              1.2 × 10.sup.4                                                                 2.2                                   31  95.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              2.000                                                                              152     11.6                                                                              1.4 × 10.sup.4                                                                 2.0                                   32* 94.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              3.000                                                                              168     9.5                                                                               6 × 10.sup.3                                                                   2.0                                   33* 96.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0   180     8.0                                                                               6 × 10.sup.3                                                                   10.0                                  34  96.899                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0.001                                                                              192     8.3                                                                               8 × 10.sup.3                                                                   9.0                                   35  96.800                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0.100                                                                              209     8.4                                                                               1.1 × 10.sup.4                                                                 8.9                                   36  94.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              2.000                                                                              213     8.9                                                                               1.4 × 10.sup.4                                                                 8.8                                   37* 93.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              3.000                                                                              255     9.1                                                                               5 × 10.sup.3                                                                   8.3                                   38* 94.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0    75     7.2                                                                               7 × 10.sup.3                                                                   3.8                                   39  94.898                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0.001                                                                               84     7.4                                                                               9 × 10.sup.3                                                                   2.7                                   40  94.799                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0.100                                                                               95     9.0                                                                               9 × 10.sup.3                                                                   2.4                                   41  92.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              2.000                                                                              112     10.0                                                                              1.1 × 10.sup.4                                                                 2.0                                   42* 91.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              3.000                                                                              121     10.2                                                                              6 × 10.sup.3                                                                   2.0                                   43* 93.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0    82     7.6                                                                               7 × 10.sup.3                                                                   3.9                                   44  93.899                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0.001                                                                               95     8.1                                                                               1 × 10.sup.4                                                                   2.8                                   45  93.800                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0.100                                                                              102     9.9                                                                               1.2 × 10.sup.4                                                                 2.6                                   46  91.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              2.000                                                                              109     10.2                                                                              1.1 × 10.sup.4                                                                 2.3                                   47* 90.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              3.000                                                                              123     10.5                                                                              5 × 10.sup.3                                                                   2.2                                   48* 92.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0    95     8.4                                                                               7 × 10.sup.3                                                                   9.4                                   49  92.899                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0.001                                                                              108     9.0                                                                               8 × 10.sup.3                                                                   9.3                                   50  92.800                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0.100                                                                              119     10.8                                                                              9 × 10.sup.3                                                                   8.0                                   51  90.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              2.000                                                                              124     12.0                                                                              1 × 10.sup.4                                                                   8.0                                   52* 89.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              3.000                                                                              148     10.1                                                                              7 × 10.sup.3                                                                   7.2                                   53* 92.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0    40     4.0                                                                               6 × 10.sup.3                                                                   6.2                                   54* 92.898                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0.001                                                                               53     4.2                                                                               7 × 10.sup.3                                                                   6.1                                   55* 92.799                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0.100                                                                               56     4.3                                                                               8 × 10.sup.3                                                                   5.8                                   56* 90.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              2.000                                                                               64     6.0                                                                               8 × 10.sup.3                                                                   6.0                                   57* 89.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              3.000                                                                               71     5.3                                                                               7 × 10.sup.3                                                                   5.9                                   58* 91.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0    49     4.4                                                                               6 × 10.sup.3                                                                   10.2                                  59* 91.988                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0.001                                                                               60     4.4                                                                               8 × 10.sup.3                                                                   9.2                                   60* 91.800                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0.100                                                                               64     5.0                                                                               8 × 10.sup.3                                                                   8.9                                   61* 89.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              2.000                                                                               84     7.0                                                                               7 × 10.sup.3                                                                   9.0                                   62* 88.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              3.000                                                                               92     6.0                                                                               7 × 10.sup.3                                                                   9.1                                   63* 95.800                                                                             0.100                                                                              1.000                                                                              3.000                                                                              0.100                                                                              194     7.2                                                                               4 × 10.sup.3                                                                   19.2                                  64* 92.900                                                                             0.100                                                                              1.000                                                                              3.000                                                                              3.000                                                                              281     6.6                                                                               3 × 10.sup.3                                                                   18.0                                  __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 3

SrTiO₃, Nb₂ O₅, Ta₂ O₅, MnO₂ and BaO are made in a composition ratio shown in the below-mentioned Table 3, and mixing, forming and firings are carried out in a similar operation as the above-mentioned Example 1, and measurements are made in the similar conditions and results are shown in Table 3.

                                      TABLE 3                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                          Characteristic value                                   No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Ta.sub.2 O.sub.5                                                                   MnO.sub.2                                                                          BaO V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                            tan δ (%)                       __________________________________________________________________________      1* 99.795                                                                             0.100                                                                              0   0.100                                                                              0.005                                                                              1300    3.4                                                                               1 × 10.sup.3                                                                   5.2                                    2* 99.300                                                                             0.100                                                                              0   0.500                                                                              0.100                                                                              1550    5.0                                                                               2 × 10.sup.3                                                                   8.3                                    3* 99.899                                                                             0.100                                                                              0.001                                                                              0   0    90     3.0                                                                               1 × 10.sup.3                                                                   4.2                                    4* 99.898                                                                             0.100                                                                              0.001                                                                              0   0.001                                                                               98     4.1                                                                               1 × 10.sup.3                                                                   2.8                                    5* 99.799                                                                             0.100                                                                              0.001                                                                              0   0.100                                                                              105     4.8                                                                               3 × 10.sup.3                                                                   2.1                                    6* 97.899                                                                             0.100                                                                              0.001                                                                              0   2.000                                                                              121     5.6                                                                               3 × 10.sup.3                                                                   2.0                                    7* 96.899                                                                             0.100                                                                              0.001                                                                              0   3.000                                                                              155     5.9                                                                               1 × 10.sup.3                                                                   1.9                                    8* 99.898                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0   100     5.7                                                                               4 × 10.sup.3                                                                   4.1                                   9   99.897                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0.001                                                                              102     8.6                                                                               8 × 10.sup.3                                                                   2.7                                   10  99.798                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0.100                                                                              111     9.8                                                                               8 × 10.sup.3                                                                   2.0                                   11  97.799                                                                             0.100                                                                              0.001                                                                              0.001                                                                              2.000                                                                              135     10.5                                                                              9 × 10.sup.3                                                                   2.0                                   12* 96.799                                                                             0.100                                                                              0.001                                                                              0.001                                                                              3.000                                                                              150     11.2                                                                              5 × 10.sup.3                                                                   2.0                                   13* 98.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0   150     8.2                                                                               4 × 10.sup.3                                                                   4.5                                   14  98.898                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0.001                                                                              152     8.9                                                                               8 × 10.sup.3                                                                   3.0                                   15  98.799                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0.100                                                                              160     10.1                                                                              9 × 10.sup.3                                                                   2.6                                   16  96.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              2.000                                                                              168     11.4                                                                              1 × 10.sup.4                                                                   2.3                                   17* 95.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              3.000                                                                              172     11.8                                                                              5 × 10.sup.3                                                                   2.2                                   18* 97.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0   190     8.8                                                                               5 × 10.sup.3                                                                   10.1                                  19  97.898                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0.001                                                                              205     9.0                                                                               9 × 10.sup.3                                                                   9.2                                   20  97.799                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0.100                                                                              215     10.4                                                                              1.1 × 10.sup.4                                                                 9.1                                   21  95.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              2.000                                                                              230     11.9                                                                              1 × 10.sup.4                                                                   8.0                                   22* 94.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              3.000                                                                              254     10.5                                                                              7 × 10.sup. 3                                                                  6.9                                   23* 98.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0    90     8.0                                                                               4 × 10.sup.3                                                                   4.0                                   24  98.898                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0.001                                                                               93     9.1                                                                               8 × 10.sup.3                                                                   2.8                                   25  98.799                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0.100                                                                              100     11.4                                                                              9 × 10.sup.3                                                                   2.6                                   26  96.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              2.000                                                                              120     12.0                                                                              1 × 10.sup.4                                                                   2.5                                   27* 95.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              3.000                                                                              140     10.1                                                                              6 × 10.sup.3                                                                   2.3                                   28* 97.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0   130     8.2                                                                               5 × 10.sup.3                                                                   4.2                                   29  97.899                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0.001                                                                              135     9.3                                                                               9 × 10.sup.3                                                                   2.9                                   30  97.800                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0.100                                                                              148     12.1                                                                              1.1 × 10.sup.4                                                                 2.1                                   31  95.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              2.000                                                                              150     11.8                                                                              1.3 × 10.sup.4                                                                 2.1                                   32* 94.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              3.000                                                                              164     10.0                                                                              6 × 10.sup.3                                                                   2.0                                   33* 96.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0   180     8.0                                                                               6 × 10.sup.3                                                                   10.0                                  34  96.899                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0.001                                                                              190     8.5                                                                               8 × 10.sup.3                                                                   9.2                                   35  96.800                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0.100                                                                              204     8.9                                                                               1 × 10.sup.4                                                                   9.0                                   36  94.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              2.000                                                                              210     9.4                                                                               1.3 × 10.sup.4                                                                 8.8                                   37* 93.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              3.000                                                                              245     9.5                                                                               8 × 10.sup.3                                                                   8.1                                   38* 94.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0    75     7.2                                                                               7 × 10.sup.3                                                                   3.8                                   39  94.898                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0.001                                                                               81     7.9                                                                               9 × 10.sup.3                                                                   2.9                                   40  94.799                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0.100                                                                               85     9.9                                                                               1 × 10.sup.4                                                                   2.5                                   41  92.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              2.000                                                                              100     10.4                                                                              1.2 × 10.sup.4                                                                 2.1                                   42* 91.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              3.000                                                                              115     11.0                                                                              6 × 10.sup.3                                                                   2.0                                   43* 93.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0    82     7.6                                                                               7 × 10.sup.3                                                                   3.9                                   44  93.899                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0.001                                                                               85     8.3                                                                               9 × 10.sup.3                                                                   2.9                                   45  93.800                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0.100                                                                               97     10.1                                                                              1.1 × 10.sup.4                                                                 2.6                                   46  91.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              2.000                                                                              108     11.2                                                                              1 × 10.sup.4                                                                   2.2                                   47* 90.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              3.000                                                                              120     10.7                                                                              5 × 10.sup.3                                                                   2.1                                   48* 92.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0    95     8.4                                                                               7 × 10.sup.3                                                                   9.4                                   49  92.899                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0.001                                                                              102     9.2                                                                               8 × 10.sup.3                                                                   9.3                                   50  92.800                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0.100                                                                              114     11.0                                                                              1 × 10.sup.4                                                                   8.1                                   51  90.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              2.000                                                                              123     12.3                                                                              1 × 10.sup.4                                                                   8.0                                   52* 89.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              3.000                                                                              147     10.4                                                                              7 × 10.sup.3                                                                   7.4                                   53* 92.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0    40     4.0                                                                               6 × 10.sup.3                                                                   6.2                                   54* 92.898                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0.001                                                                               43     4.4                                                                               7 × 10.sup.3                                                                   6.0                                   55* 92.799                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0.100                                                                               49     4.5                                                                               8 × 10.sup.3                                                                   5.8                                   56* 90.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              2.000                                                                               52     6.2                                                                               9 × 10.sup.3                                                                   5.9                                   57* 89.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              3.000                                                                               69     5.8                                                                               7 × 10.sup.3                                                                   5.8                                   58* 91.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0    49     4.4                                                                               6 × 10.sup.3                                                                   10.2                                  59* 91.899                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0.001                                                                               55     4.8                                                                               8 × 10.sup.3                                                                   9.4                                   60* 91.800                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0.100                                                                               62     5.5                                                                               8 × 10.sup.3                                                                   9.1                                   61* 89.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              2.000                                                                               84     7.2                                                                               8 × 10.sup.3                                                                   9.0                                   62* 88.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              3.000                                                                               93     6.1                                                                               7 × 10.sup.3                                                                   8.5                                   63* 95.800                                                                             0.100                                                                              1.000                                                                              3.000                                                                              0.100                                                                              131     8.2                                                                               5 × 10.sup.3                                                                   19.7                                  64* 92.900                                                                             0.100                                                                              1.000                                                                              3.000                                                                              3.000                                                                              249     9.1                                                                               4 × 10.sup.3                                                                   18.0                                  __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 4

SrTiO₃, Nb₂ O₅, Ta₂ O₅, MnO₂ and HfO₂ are made in a composition ratio shown in the below-mentioned Table 4, and mixing, forming and firings are carried out in a similar operation as the above-mentioned Example 1, and measurements are made in the similar conditions and results are shown in Table 4.

                                      TABLE 4                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                          Characteristic value                                   No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Ta.sub.2 O.sub.5                                                                   MnO.sub.2                                                                          HfO.sub.2                                                                          V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                            tan δ (%)                       __________________________________________________________________________      1* 99.795                                                                             0.100                                                                              0   0.100                                                                              0.005                                                                              1220    3.5                                                                               1 × 10.sup.3                                                                   6.4                                    2* 99.300                                                                             0.100                                                                              0   0.500                                                                              0.100                                                                              1470    5.6                                                                               2 × 10.sup.3                                                                   11.8                                   3* 99.899                                                                             0.100                                                                              0.001                                                                              0   0    90     3.0                                                                               1 × 10.sup.3                                                                   4.2                                    4* 99.898                                                                             0.100                                                                              0.001                                                                              0   0.001                                                                              130     4.2                                                                               1 × 10.sup.3                                                                   3.9                                    5* 99.799                                                                             0.100                                                                              0.001                                                                              0   0.100                                                                              135     4.9                                                                               2 × 10.sup.3                                                                   3.3                                    6* 97.899                                                                             0.100                                                                              0.001                                                                              0   2.000                                                                              137     5.5                                                                               4 × 10.sup.3                                                                   3.0                                    7* 96.899                                                                             0.100                                                                              0.001                                                                              0   3.000                                                                              194     5.4                                                                               3 × 10.sup.3                                                                   4.5                                    8* 99.898                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0   100     5.7                                                                               4 × 10.sup.3                                                                   4.1                                   9   99.897                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0.001                                                                              135     8.6                                                                               8 × 10.sup.3                                                                   3.7                                   10  99.798                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0.100                                                                              142     9.7                                                                               9 × 10.sup.3                                                                   3.2                                   11  97.799                                                                             0.100                                                                              0.001                                                                              0.001                                                                              2.000                                                                              160     9.8                                                                               9 × 10.sup.3                                                                   2.9                                   12* 96.799                                                                             0.100                                                                              0.001                                                                              0.001                                                                              3.000                                                                              184     9.4                                                                               5 × 10.sup.3                                                                   3.8                                   13* 98.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0   150     8.2                                                                               4 × 10.sup.3                                                                   4.5                                   14  98.898                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0.001                                                                              172     8.8                                                                               9 × 10.sup.3                                                                   4.1                                   15  98.799                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0.100                                                                              181     9.7                                                                               9 × 10.sup.3                                                                   3.5                                   16  96.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              2.000                                                                              185     9.9                                                                               1.1 × 10.sup.4                                                                 3.0                                   17* 95.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              3.000                                                                              202     9.1                                                                               6 × 10.sup.3                                                                   7.2                                   18* 97.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0   190     8.8                                                                               5 × 10.sup.3                                                                   10.1                                  19  97.898                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0.001                                                                              208     8.0                                                                               9 × 10.sup.3                                                                   10.0                                  20  97.799                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0.100                                                                              219     8.6                                                                               1 × 10.sup.4                                                                   9.2                                   21  95.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              2.000                                                                              224     8.5                                                                               1.1 × 10.sup.4                                                                 8.9                                   22* 94.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              3.000                                                                              275     7.8                                                                               6 × 10.sup.3                                                                   7.9                                   23* 98.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0    90     8.0                                                                               4 × 10.sup.3                                                                   4.0                                   24  98.898                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0.001                                                                              114     9.2                                                                               9 × 10.sup.3                                                                   2.8                                   25  98.799                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0.100                                                                              127     11.3                                                                              1 × 10.sup.4                                                                   2.3                                   26  96.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              2.000                                                                              141     11.5                                                                              1.1 × 10.sup.4                                                                 2.3                                   27* 95.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              3.000                                                                              176     9.0                                                                               6 × 10.sup.3                                                                   6.4                                   28* 97.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0   130     8.2                                                                               5 × 10.sup.3                                                                   4.2                                   29  97.899                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0.001                                                                              159     9.2                                                                               9 × 10.sup.3                                                                   3.0                                   30  97.800                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0.100                                                                              169     12.0                                                                              9 × 10.sup.3                                                                   2.6                                   31  95.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              2.000                                                                              175     11.4                                                                              1.1× 10.sup.4                                                                  2.3                                   32* 94.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              3.000                                                                              200     9.1                                                                               7 × 10.sup.3                                                                   5.5                                   33* 96.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0   180     8.0                                                                               6 × 10.sup.3                                                                   10.0                                  34  96.899                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0.001                                                                              205     8.0                                                                               7 × 10.sup.3                                                                   9.6                                   35  96.800                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0.100                                                                              221     8.0                                                                               7 × 10.sup.3                                                                   9.1                                   36  94.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              2.000                                                                              245     8.1                                                                               8 × 10.sup.3                                                                   8.9                                   37* 93.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              3.000                                                                              280     6.8                                                                               9 × 10.sup.3                                                                   8.9                                   38* 94.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0    75     7.2                                                                               7 × 10.sup.4                                                                   3.8                                   39  94.898                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0.001                                                                              100     7.8                                                                               7 × 10.sup.3                                                                   3.2                                   40  94.799                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0.100                                                                              106     9.4                                                                               8 × 10.sup.3                                                                   2.7                                   41  92.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              2.000                                                                              130     9.8                                                                               9 × 10.sup.3                                                                   2.4                                   42* 91.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              3.000                                                                              147     8.9                                                                               4 × 10.sup.3                                                                   3.6                                   43* 93.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0    82     7.6                                                                               7 × 10.sup.3                                                                   3.9                                   44  93.899                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0.001                                                                              109     8.5                                                                               9 × 10.sup.3                                                                   2.8                                   45  93.800                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0.100                                                                              125     10.3                                                                              1.1 × 10.sup.4                                                                 2.7                                   46  91.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              2.000                                                                              135     10.2                                                                              1.2 × 10.sup.4                                                                 2.5                                   47* 90.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              3.000                                                                              169     9.3                                                                               6 × 10.sup.3                                                                   4.4                                   48* 92.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0    95     8.4                                                                               7 × 10.sup.3                                                                   9.4                                   49* 92.899                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0.001                                                                              135     9.0                                                                               7 × 10.sup. 3                                                                  9.4                                   50* 92.800                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0.100                                                                              142     10.1                                                                              8 × 10.sup.3                                                                   9.1                                   51* 90.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              2.000                                                                              158     10.0                                                                              8 × 10.sup.3                                                                   8.6                                   52* 89.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              3.000                                                                              211     8.2                                                                               4 × 10.sup.3                                                                   9.3                                   53* 92.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0    40     4.0                                                                               6 × 10.sup.3                                                                   6.2                                   54* 92.898                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0.001                                                                               71     4.4                                                                               7 × 10.sup.3                                                                   6.2                                   55* 92.799                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0.100                                                                               78     4.3                                                                               6 × 10.sup.3                                                                   6.0                                   56* 90.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              2.000                                                                               89     4.3                                                                               6 × 10.sup.3                                                                   5.9                                   57* 89.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              3.000                                                                              128     4.0                                                                               6 × 10.sup.3                                                                   7.9                                   58* 91.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0    49     4.4                                                                               6 × 10.sup.3                                                                   10.2                                  59* 91.899                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0.001                                                                               88     4.8                                                                               7 × 10.sup.3                                                                   10.2                                  60* 91.800                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0.100                                                                               91     5.1                                                                               6 × 10.sup.3                                                                   10.1                                  61* 89.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              2.000                                                                              104     5.0                                                                               6 × 10.sup.3                                                                   10.0                                  62* 88.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              3.000                                                                              144     4.2                                                                               4 × 10.sup.3                                                                   10.0                                  63* 95.800                                                                             0.100                                                                              1.000                                                                              3.000                                                                              0.100                                                                              215     6.2                                                                               4 × 10.sup.3                                                                   28.0                                  64* 92.900                                                                             0.100                                                                              1.000                                                                              3.000                                                                              3.000                                                                              272     5.0                                                                               4 × 10.sup.3                                                                   22.4                                  __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 5

SrTiO₃, Nb₂ O₅, Ta₂ O₅, MnO₂ and ZrO₂ are made in a composition ratio shown in the below-mentioned Table 5, and mixing, forming and firings are carried out in a similar operation as the above-mentioned Example 1, and measurements are made in the similar conditions and results are shown in Table 5.

                                      TABLE 5                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                          Characteristic value                                   No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Ta.sub.2 O.sub.5                                                                   MnO.sub.2                                                                          ZrO.sub.2                                                                          V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                            tan δ (%)                       __________________________________________________________________________      1* 99.795                                                                             0.100                                                                              0   0.100                                                                              0.005                                                                              1340    3.4                                                                               1 × 10.sup.3                                                                   6.4                                    2* 99.300                                                                             0.100                                                                              0   0.500                                                                              0.100                                                                              1520    5.5                                                                               2 × 10.sup.3                                                                   11.4                                   3* 99.899                                                                             0.100                                                                              0.001                                                                              0   0    90     3.0                                                                               1 × 10.sup.3                                                                   4.2                                    4* 99.898                                                                             0.100                                                                              0.001                                                                              0   0.001                                                                              105     4.1                                                                               1 × 10.sup.3                                                                   3.7                                    5* 99.799                                                                             0.100                                                                              0.001                                                                              0   0.100                                                                              112     4.8                                                                               2 × 10.sup.3                                                                   3.0                                    6* 97.899                                                                             0.100                                                                              0.001                                                                              0   2.000                                                                              134     5.6                                                                               2 × 10.sup.3                                                                   3.0                                    7* 96.899                                                                             0.100                                                                              0.001                                                                              0   3.000                                                                              174     5.7                                                                               3 × 10.sup.3                                                                   4.5                                    8* 99.898                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0   100     5.7                                                                               4 × 10.sup.3                                                                   4.1                                   9   99.897                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0.001                                                                              115     8.5                                                                               7 × 10.sup.3                                                                   3.6                                   10  99.798                                                                             0.100                                                                              0.001                                                                              0.001                                                                              0.100                                                                              123     9.6                                                                               9 × 10.sup.3                                                                   3.0                                   11  97.799                                                                             0.100                                                                              0.001                                                                              0.001                                                                              2.000                                                                              141     9.7                                                                               9 × 10.sup.3                                                                   2.9                                   12* 96.799                                                                             0.100                                                                              0.001                                                                              0.001                                                                              3.000                                                                              163     10.0                                                                              5 × 10.sup.3                                                                   3.8                                   13* 98.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0   150     8.2                                                                               4 × 10.sup.3                                                                   4.5                                   14  98.898                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0.001                                                                              152     8.6                                                                               8 × 10.sup.3                                                                   4.1                                   15  98.799                                                                             0.100                                                                              0.001                                                                              1.000                                                                              0.100                                                                              163     9.5                                                                               9 × 10.sup.3                                                                   3.5                                   16  96.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              2.000                                                                              172     9.9                                                                               1 × 10.sup.4                                                                   3.0                                   17* 95.899                                                                             0.100                                                                              0.001                                                                              1.000                                                                              3.000                                                                              181     9.4                                                                               6 × 10.sup.3                                                                   7.0                                   18* 97.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0   190     8.8                                                                               5 × 10.sup.3                                                                   10.1                                  19  97.898                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0.001                                                                              193     8.2                                                                               9 × 10.sup.3                                                                   10.0                                  20  97.799                                                                             0.100                                                                              0.001                                                                              2.000                                                                              0.100                                                                              198     9.0                                                                               1 × 10.sup.4                                                                   9.2                                   21  95.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              2.000                                                                              203     9.7                                                                               1.1 × 10.sup.4                                                                 8.7                                   22* 94.899                                                                             0.100                                                                              0.001                                                                              2.000                                                                              3.000                                                                              254     9.7                                                                               6 × 10.sup.3                                                                   7.4                                   23* 98.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0    90     8.0                                                                               4 ×  10.sup.3                                                                  4.0                                   24  98.898                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0.001                                                                               97     9.1                                                                               8 × 10.sup.3                                                                   2.8                                   25  97.799                                                                             0.100                                                                              1.000                                                                              0.001                                                                              0.100                                                                              104     11.2                                                                              9 × 10.sup.3                                                                   2.4                                   26  96.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              2.000                                                                              126     11.7                                                                              1 × 10.sup.4                                                                   2.3                                   27* 95.899                                                                             0.100                                                                              1.000                                                                              0.001                                                                              3.000                                                                              155     10.0                                                                              6 × 10.sup.3                                                                   6.1                                   28* 97.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0   130     8.2                                                                               5 × 10.sup.3                                                                   4.2                                   29  97.899                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0.001                                                                              143     9.1                                                                               9 × 10.sup.3                                                                   3.0                                   30  97.800                                                                             0.100                                                                              1.000                                                                              1.000                                                                              0.100                                                                              151     11.9                                                                              1 × 10.sup.4                                                                   2.4                                   31  95.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              2.000                                                                              155     11.5                                                                              1.1 × 10.sup.4                                                                 2.2                                   32* 94.900                                                                             0.100                                                                              1.000                                                                              1.000                                                                              3.000                                                                              174     9.4                                                                               7 × 10.sup.3                                                                   5.4                                   33* 96.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0   180     8.0                                                                               6 × 10.sup.3                                                                   10.0                                  34  96.899                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0.001                                                                              194     8.1                                                                               7 × 10.sup.3                                                                   9.4                                   35  96.800                                                                             0.100                                                                              1.000                                                                              2.000                                                                              0.100                                                                              209     8.2                                                                               7 × 10.sup.3                                                                   8.9                                   36  94.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              2.000                                                                              231     8.7                                                                               8 × 10.sup.3                                                                   8.8                                   37* 93.900                                                                             0.100                                                                              1.000                                                                              2.000                                                                              3.000                                                                              258     8.9                                                                               5 × 10.sup.3                                                                   8.8                                   38* 94.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0    75     7.2                                                                               7 × 10.sup.3                                                                   3.8                                   39  94.898                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0.001                                                                               83     7.6                                                                               8 × 10.sup.3                                                                   2.9                                   40  94.799                                                                             0.100                                                                              5.000                                                                              0.001                                                                              0.100                                                                               94     9.2                                                                               9 × 10.sup.3                                                                   2.4                                   41  92.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              2.000                                                                              110     9.9                                                                               1 × 10.sup.4                                                                   2.3                                   42* 91.899                                                                             0.100                                                                              5.000                                                                              0.001                                                                              3.000                                                                              126     10.0                                                                              6 × 10.sup.3                                                                   3.6                                   43* 93.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0    82     7.6                                                                               7 × 10.sup.3                                                                   3.9                                   44  93.899                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0.001                                                                               93     8.3                                                                               9 × 10.sup.3                                                                   2.7                                   45  93.800                                                                             0.100                                                                              5.000                                                                              1.000                                                                              0.100                                                                              100     10.1                                                                              1 × 10.sup.4                                                                   2.6                                   46  91.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              2.000                                                                              107     10.0                                                                              9 × 10.sup.3                                                                   2.6                                   47* 90.900                                                                             0.100                                                                              5.000                                                                              1.000                                                                              3.000                                                                              134     9.7                                                                               5 × 10.sup.3                                                                   4.2                                   48* 92.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0    95     8.4                                                                               7 × 10.sup.3                                                                   9.4                                   49* 92.899                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0.001                                                                              112     9.0                                                                               7 × 10.sup.3                                                                   9.4                                   50* 92.800                                                                             0.100                                                                              5.000                                                                              2.000                                                                              0.100                                                                              124     10.1                                                                              7 × 10.sup.3                                                                   9.1                                   51* 90.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              2.000                                                                              128     10.3                                                                              8 × 10.sup.3                                                                   8.5                                   52* 89.900                                                                             0.100                                                                              5.000                                                                              2.000                                                                              3.000                                                                              192     9.1                                                                               5 × 10.sup.3                                                                   9.0                                   53* 92.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0    40     4.0                                                                               6 × 10.sup.3                                                                   6.2                                   54* 92.898                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0.001                                                                               58     4.5                                                                               6 × 10.sup.3                                                                   6.0                                   55* 92.799                                                                             0.100                                                                              7.000                                                                              0.001                                                                              0.100                                                                               62     4.6                                                                               6 × 10.sup.3                                                                   5.8                                   56* 90.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              2.000                                                                               69     6.2                                                                               7 × 10.sup.3                                                                   5.8                                   57* 89.899                                                                             0.100                                                                              7.000                                                                              0.001                                                                              3.000                                                                               99     4.9                                                                               5 × 10.sup.3                                                                   7.1                                   58* 91.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0    49     4.4                                                                               6 × 10.sup.3                                                                   10.2                                  59* 91.899                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0.001                                                                               74     4.9                                                                               6 × 10.sup.3                                                                   10.0                                  60* 91.800                                                                             0.100                                                                              7.000                                                                              1.000                                                                              0.100                                                                               80     5.5                                                                               6 × 10.sup.3                                                                   9.9                                   61* 89.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              2.000                                                                               91     6.8                                                                               6 × 10.sup.3                                                                   9.8                                   62* 88.900                                                                             0.100                                                                              7.000                                                                              1.000                                                                              3.000                                                                              122     5.3                                                                               5 × 10.sup.3                                                                   9.9                                   63* 95.800                                                                             0.100                                                                              1.000                                                                              3.000                                                                              0.100                                                                              197     6.5                                                                               4 ×  10.sup.3                                                                  20.5                                  64* 92.900                                                                             0.100                                                                              1.000                                                                              3.000                                                                              3.000                                                                              227     6.3                                                                               4 × 10.sup.3                                                                   18.4                                  __________________________________________________________________________      *Comparison sample                                                       

As shown by Examples 1 to 5, Nb₂ O₅ and Ta₂ O₅ dissolve as solid solution into the crystal having SrTiO₃ as host material at the reduced firing and thereby to reduce specific resistance of the fired body by about 1.0 Ωcm by atomic valency controlling, and therefore, by refiring in the air it shows varistor characteristics such that high resitance layers are formed at the grain boundaries of the fired bodies.

And, Nb₂ O₅ is contained in TiO₂ in the material as inclusion, and is contained in 0.001-0.200 mol % in the raw material usually to be industrically refined. In case the SrTiO₃ is semiconductorized only with Nb₂ O₅ the specific resistance becomes rather high, and the characteristic is unstable though it shows the varistor characteristics. But by addition of Ta₂ O₅ to Nb₂ O₅, the specific resistance can be lowered, and stable characteristics are obtainable. When the added amount of Ta₂ O₅ is too much, dissolution as solid solution of other additives is hindered, and accordingly 0.001-5.000 mol % of it is appropriate.

By making segregation at granule boundaries by addition of MnO₂, the granule boundaries is changed to a high resistance value and the energy barrier of the granule boundaries. Therefore, by the addition of MnO₂, the non-linearity exponent α becomes large and at the same time the varistor voltage becomes high.

Besides, by the addition of MnO₂ the high resistance region of the granule boundaries expands, and accordingly this means that thickness of the insulation layer increases, and thereby the dielectric constant decreases.

Since MnO₂ takes plural valency, there is a possibility of producing hopping conduction between different Mn valency. Therefore, when the amount of addition of MnO₂ increases the tan δ becomes large, to induce a cause of deterioration of the characteristic. Accordingly, as the amount of addition of MnO₂, 0.001-2.000 mol % is appropriate. When La, Cu, Y, Mo, Pb and W are added, for the amount of MnO₂, a range of 0.001 to 0.01 mole % is desirable for Na an amount of 0.001 to 0.02 mol % is desirable.

When at least one element selected from the group consisting of Ga, Pt, Tl, Si, Ti, Li, La, Cu, Y, Cs, Au, Mo, S, Be, Al, Na, K, Ca, Cd, In, Ba, Pb, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf, Ru, Mg, Zr, Sn, Sb and W is added at the same time, it is possible to increase the dielectric constant and decrease the tan δ, without changing the non-linearity exponent α increased by MnO₂, to greatly improve the characteristic, but the dielectric constant becomes small when the amount of addition becomes much; and accordingly 0.001-2.000 mol % is appropriate.

Though in the examples, only the cases where Ga, Pt, Tl, Si, Ti, Li, La, Cu, Y, Cs, Au, Mo, S, Be, Al, Na, K, Ca, Cd, In, Ba, Pb, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf, Ru, Mg, Zr, Sn, Sb and W are added each as simple substance, it is confirmed that even when plural kinds of elements are added within the determined amount at the same time, the same effect is obtainable.

A noise filter as shown in FIG. 4 is constituted by using the elements 7 on which electrodes are provided by conductive material such as Ag and a coil 8, and noise input A shown in FIG. 5 is impressed, and thereby noise output B is obtained.

As is obvious from this, noise is sufficiently removed, and that number of components is decreased by combining the simple body element and a coil, and a miniaturization becomes possible.

POSSIBLE UTILIZATION IN INDUSTRY

As has been elucidated, according to the voltage-dependent non-linear resistance ceramic composition, absorption of surge impressed on the electric and electronic apparatuses and elimination of noise can be done by a single element, and it has many functions and can be miniaturized and is indispensable for protection of semiconductor product of the electric and electronic apparatuses, and practical utility thereof is extremely great. 

We claim:
 1. A voltage-dependent non-linear resistance ceramic composition consisting essentially of:90.800-99.996 mol % of SrTiO₃, 0.001-0.200 mol % of Nb₂ O₅, 0.001-5.000 mol % of Ta₂ O₅, 0.001-2.000 mol % of MnO₂, and 0.001-2.000 mol % of an oxide of at least one of element selected from the group consisting of Ga, Pt, Tl, Si, Ti, Cs, Au, S, Be, Al, Ca, Cd, In, Ba, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf, Ru, Mg, Zr, Sn and Sb. 